Possible Clues:

• Double vision?
• Lens created by Ben Franklin
• Accept, say, free of charge almost every description of viewing aid
• New FBI commander and gangster on the bridge looking both ways
• Like Ben Franklin's glasses
• Like two-part lenses
• Of dual-purpose lenses
• Heading out of pub after retracting lie that's seen through
• Dual-purpose, as lenses
• Dual-purpose bit of eyewear